High pressure fuel pumps



? Feb. 8,1966 5. r. SMITH I 3,

HIGH PRESSURE FUEL PUMPS Filed April 24, 1963 2 Sheets-Sheet 1 INVENTORWTW 1966 s. T. SMITH 3,233,550

. HIGH PRESSURE FUEL PUMPS Filed April 24, 1965 3 Sheets-Sheet z3,233,550 HIGH PRESSURE FUEL PUMPS Sidney T. Smith, Box 50, Rte. 1,Grafton, W. Va. Filed Apr. 24, 1963, Ser. No. 275,340 3 Claims. (Cl.10338) This invention relates to improvements in high pressure \fuelpumps such as are used on diesel motors. Several pumps of this type havebeen patented, differing mainly in their means of metering the fuel.This pump follows that pattern. In this device, the metering isaccomplished by rotating One ring with inclined planed surfacescoaxially disposed around the pump axis against another ring of similardesign but having the inclined planed surfaces slanted in the oppositedirection and held stationary so as to force the two rings fartherapart. This action raises the rotor and cam which when the motor isoperating, produces a longer stroke in the pump barrel and results in aheavier charge of fuel to the engine cylinder being served.

This pump, if built in sufficiently substantial proportions and ofproper materials, should endure the high pressures generated in a highpressure pump over long periods of service. Furthermore, the simplicityof design and low number of working parts should make for economy inmanufacture.

In the drawings;

FIG. 1 is a vertical sectional View of a fuel pump in accordance withthis invention.

FIG. 2 is an inverted view of the ring 20.

FIG. 3 is a side view of the rings showing the outer edges of theinclined planed surfaces.

FIG. 4 is a top view of the rotor and cam assembly.

FIG. 5 is a side View of the rotor.

Referring now more particularly to the characters of reference in thedrawings; this pump comprises a main body 1 of generally cylindricalform, such body including at the bottom, a collar for bolting on thelower body 2 which holds the driving and metering equipment. Theseinclude a drive shaft 2 3, splined at the upper end, the rotor 16 with aslot in its center, splined to lit on the upper end of the drive shaft,and the two rings and 21 with the inclined planed surfaces opposed.

The main body 1 is formed with a prescribed number of bores coaxiallydisposed and evenly spaced, which hold the pump barrels 4, and thetappets 13. The barrels 4 are threaded at the upper ends to receive theplugs which hold the fuel lines 10 in place, which conduct fuel toengine cylinders. Cam advanced and spring retracted plungers 9 work inthe barrels 4, forced up by the tappets 13 and the cam 15. Helicalsprings v12 surround the plungers 9 at their lower ends and, workingbetween the lower end of the barrel and the guidehead 11 on the lowerend of the plungers, serve to retract the plungers after the pressurestroke.

Each pump barrel 4 together with its enclosed plunger 9 and the relatedworking parts form what may be termed a fuel metering and distributingunit. One of these units is allotted to each of the cylinders in theengine being served.

The body 1 contains in its center a fuel reservoir 5 fed by a constantdelivery pump 27 of about twenty-five pounds pressure. From thisreservoir the fuel is fed to the surrounding pump barrels thru checkvalves 7 and canals 6 and 8. When the plunger 9 is retracted the lowpressure fuel from the reservoir 5 is fed into the pump barrels 4 and onthe succeding pressure stroke, when the motor is in operation, a chargeof fuel is forced thru the fuel line 10 into the engine cylinder beingserved. The check valves 7 are not indispensible to the working efii-United States Patent 0 ciency of the pump. They serve only to make ashorter plunger stroke adequate.

The rings 20 and 21 with the inclined planed surfaces opposed constitutethe basis of this device for which a patent is sought. The ring 20 isheld from turning by the lugs 19 on its sides which are held by ribs 18in the inside of the lower body 2. When lever 22 is moved in a clockwisedirection, as seen from its upper side, ring 21 moves with it and, bythe action of the opposed inclined planed surfaces working against eachother, forces ring 20, which cannot turn, to a higher position. Rotor 16and cam 15, supported by ring 20, are moved up with it and, when thepump is in operation, the tappet 1-3 and-the plunger 9 are given alonger pressure stroke, resulting in a heavier charge of fuel to theengine cylinder being served. When the cam 15 passes the nub 14 thetappet 13 and the plunger 9 are pushed back to their lowest point by thespring 12 between the lower end of the pump barrel 4 and the guidehead1 1. The tappet 13 rests on the retainer plate 24 which limits thereturn stroke of the plunger 9 to a point just below canal '8. When thelever 22 is moved counterclockwise, moving ring 21 with it, somepressure is taken off ring 20 and the spring 17 moves the rotor 16 andthe ring 20 down against ring 2 1 which reduces the pressure stroke ofthe plunger 9.

The pump is mounted at its base to the motor and has a drive gear (notshown) secured on the outer end of the drive shaft 23. The drive gear isproperly meshed and timed in the timing gear train so that the chargesof fuel are delivered to the respective engine cylinders at the mosteflicient time.

The described fuel pump, while being relatively simple in its structure,is also quite rugged and provides a practical and efficient machine forthe injection of high pressure fuels into engine cylinders.

From the foregoing description it should be evident that there has beenproduced such a device as substantially fulfills the objects of theinvention as set forth herein.

While this specification sets forth in detail the preferred constructionof the device, in practice deviations from such detail may be resortedto as do not form a departure from the basic elements of the inventionas defined by the appended claims.

Having thus described the invention, the following is claimed as new anduseful, and upon which Letters Patent is sought:

-1. A fuel pump comprising a body having a cylinder therein, thecylinder having a head, a fuel outlet passage from said head, a fuelinlet passage checkval've controlled outwardly, leading to the cylindera distance from said head, a fuel pressure line leading to said inletpassage, a plunger slidable in the cylinder means to reciprocate theplunger thru a stroke of variable length, such latter means including adriven shaft, a rotary cam mounted in driving relation on the shaft andshi ftable axially thereof, one end of the plunger riding a .tappetwhich rides a cam, and applied to the cam means to shift the cam axiallyalong the shaft in one direction whereby to alter the length ofreciprocation of the plunger, said last named means comprising .anon-rotatable ring movable axially on the shaft and on which the cam isrotatably mounted, the face of the ring opposite the cam being providedwith inclined planed surfaces, coaxially disposed, riding another ringof similar design with the planed surfaces opposed, and means to turnthe opposed ring.

2. A fuel pump comprising a body having a cylinder therein, the cylinderhaving a head, a fuel outlet passage from said head, a fuel inletpassage leading to the cylinder a distance from said head, a fuelpressure line leading to said inlet passage, a plunger slidable in thecylinder,

means to reciprocate the plunger thru a stroke of variable length, suchlatter means including a driven shaft, a rotary cam mounted in drivingrelation on the sharft and shittab le axially thereof, one end of theplunger riding said cam, and applied to the cam means to shift the camaxially along the shaft in one direction, whereby to alter the length ofreciprocation of the plunger, said last named means comprising anon-rotatable rin-g, movable axially on the shaft and on which the camis rotatably mounted, the face of ring opposite the cam being providedwith inclined planed sunfaces, coaxially disposed riding another ring ofcorresponding design with the planed surfaces opposed and means to turnthe opposed ring.

3. A fuel pump comprising a body having a cylinder therein, the cylinderhaving a head, a fuel outlet passage from said head, a fuel inletpassage leading to the cylinder a distance from said head, a fuelpressure line leading to said inlet passage, a plunger slidable in thecylinder, means to reciprocate the plunger thru a stroke of constantlength from below the inlet passage to a point beyond the passage, suchlatter means including a driven shaft, a rotary cam mounted in drivingrelation on the shaft and shiftable axially thereof, one end of theplunger riding said cam, and applied to the cam means to shift the camaxially (along the shaft in one direction, whereby to alter the range ofreciprocation of the plunger, said last named means comprising anon-rotatable ring, movable axially on the shaft and on which the cam isrotatably mounted, the face of ring opposite the cam being provided withinclined planed surfaces, coaxially disposed, riding another ring ofcorresponding design with the planed surfaces opposed and means to turnthe opposed ring.

References Cited by the Examiner UNITED STATES PATENTS 2,031,346 2/1936Wahlmark 10338 2,251,552 8/1941 Purdy 10341.2 2,381,585 8/1945 Gambrell10337 2,459,303 1/ 1949 Baker 10337 2,534,153 12/1950 Widrner 103372,645,182 7/1953 Tucker 10337 LAURENCE V. EFNER, Primary Examiner.

1. A FUEL PUMP COMPRISING A BODY HAVING A CYLINDER THEREIN, THE CYLINDERHAVING A HEAD, A FUEL OUTLET PASSAGE FROM SAID HEAD, A FUEL INLETPASSAGE CHECKVALVE CONTROLLED OUTWARDLY, LEADING TO THE CYLINDER, ADISTANCE FROM SAID HEAD, A FUEL PRESSURE LINE LEADING TO SAID INLETPASSAGE, A PLUNGER SLIDABLE IN THE CYLINDER MEANS TO RECIPROCATE THEPLUNGER SLIDABLE IN THE CYLINDER MEANS TO RECIPROCATE THE INCLUDING ADRIVEN SHAFT, A ROTARY CAM MOUNTED IN DRIVING RELATION ON THE SHAFT ANDSHIFTABLE AXIALLY THEREOF, ONE END OF THE PLUNGER RIDING A TAPPET WHICHRIDES A CAM, AND APPLIED TO THE CAM MEANS TO SHIFT THE CAM AXIALLY ALONG